Electro-holographic lens

Abstract

An electro-holographic lens device comprising: an active layer made from a transparent photo-refractive material, whose refractive index may be locally modified by locally applying an electric field; an array of electrodes in a predetermined density, provided adjacent the active layer for locally providing electric fields across an array of predetermined locations in the active layer; and a control unit for applying and controlling application of electric fields in a dynamically controllable predetermined locations for creating a holographic fringe pattern across the active layer.

1. An electro-optic system for concentrating a light beam that is incident from a moving light source onto at least one predetermined target, the system comprising:
 At least one of a plurality of layers of electro-holographic lens devices comprising: 
 an active layer made from a transparent photo-refractive material, whose refractive index may be locally modified by locally applying an electric field; 
 an array of electrodes in a predetermined density, provided adjacent the active layer for locally providing electric fields across an array of predetermined locations in the active layer; 
 a tracking unit for tracking the position of the light source; 
 a control unit for applying and controlling application of electric fields in a dynamically controllable predetermined locations obtained from the tracking unit, the information relating to the location of the light source for creating a dynamically changing holographic fringe pattern across the active layer, creating a dynamically changing concentrating lens, so as to continuously focus the light beam onto the at least one predetermined target. 
 
   
   
     2. A system as claimed in  claim 1 , wherein the moving light source is the sun, and said at least one predetermined target comprises one or more photovoltaic cells. 
   
   
     3. A system as claimed in  claim 1 , wherein said at least one predetermined target is stationary. 
   
   
     4. A system as claimed in  claim 1 , further comprising a second tracking unit for tracking the momentary position of the at least one predetermined target, which is moving, and for providing the momentary position of the at least one predetermined target to the control unit for online amendment of the focusing of the light beam onto the momentary position of the at least one predetermined target. 
   
   
     5. A system as claimed in  claim 1 , where the active layer is provided on a substrate. 
   
   
     6. A system as claimed in  claim 5 , wherein the substrate is transparent. 
   
   
     7. A system as claimed in  claim 5 , wherein the substrate is reflective. 
   
   
     8. A system as claimed in  claim 1 , wherein the active layer is made from transparent materials. 
   
   
     9. A system as claimed in  claim 1 , wherein the active layer is made from materials selected from the group of colloidal semiconductors. 
   
   
     10. A system as claimed in  claim 1 , wherein the active layer is made from materials selected from the group comprising: ZnO, WO 3 , V 2 O 5 , Ag 2 O, ZnS, CdS, PbS, CuS, MoS 2 , CdSe, InO and InSnO x . 
   
   
     11. A system as claimed in  claim 1 , wherein the active layer is made from materials selected from the group of electrochromic materials. 
   
   
     12. A system as claimed in  claim 1 , wherein the active layer is made from materials selected from the group of liquid crystals. 
   
   
     13. A system as claimed in  claim 1 , wherein the target comprises at least one energy transducer for transforming the irradiated energy directed from the device onto the at least one energy transducer into electricity. 
   
   
     14. A system as claimed in  claim 13 , wherein the transducer comprises a thermal conversion unit like Stirling engine. 
   
   
     15. A system as claimed in  claim 13  wherein the transducer comprises an array of photovoltaic cells. 
   
   
     16. A system as claimed in  claim 13 , further comprising a second energy transducer, wherein the second energy transducer is sensitive to different light bandwidths from the first transducer, for receiving energy irradiations of different bandwidths. 
   
   
     17. A system as claimed in  claim 16  whereas the second transducer is adjacent the first transducer. 
   
   
     18. A system as claimed in  claim 1 , wherein the device is incorporated in a window. 
   
   
     19. A system as claimed in  claim 1 , incorporated in eyeglasses, serving as at least one lens. 
   
   
     20. A system as claimed in  claim 19 , further comprising detection means for detecting a distance between the eyeglasses and a viewed object. 
   
   
     21. A system as claimed in  claim 19 , further comprising detection means for detecting orientation of the eyes of a bearer of the eyeglasses. 
   
   
     22. A system as claimed in  claim 1 , further comprising a beam tilting element comprising at least one of the at least one of a plurality of layers of electro-holographic lens devices. 
   
   
     23. A method for concentrating a light beam that is incident from a moving light source onto at least one predetermined target, the method comprising:
 providing at least one of a plurality of layers of an electro-holographic lens devices comprising:
 an active layer made from a transparent photo-refractive material, whose refractive index may be locally modified by locally applying an electric field; 
 an array of electrodes in a predetermined density, provided adjacent the active layer for locally providing electric fields across an array of predetermined locations in the active layer; 
 a tracking unit for tracking the position of the light source; 
 a control unit for applying and controlling application of electric fields in a dynamically controllable predetermined locations based on information from the tracking unit on the position of the light source; 
 creating a dynamically changing holographic fringe pattern across the active layer thus creating a dynamically changing concentrating lens so as to continuously focus the light beam onto said at least one predetermined target. 
 
 
   
   
     24. A method as claimed in  claim 23 , wherein the moving light source is the sun, and said at least one predetermined target comprises one or more photovoltaic cells. 
   
   
     25. A method as claimed in  claim 23 , wherein said at least one predetermined target is stationary. 
   
   
     26. A method as claimed in  claim 23 , further comprising providing a second tracker and tracking the momentary position of the target using the second tracking unit for providing the momentary position of said at least one predetermined target, which is moving, to the control unit for online amendment of the focusing of the light beam onto the momentary position of the target. 
   
   
     27. A method as claimed in  claim 23 , wherein the electro-holographic lens device is refractive. 
   
   
     28. A method as claimed in  claim 23 , wherein the electro-holographic lens device is reflective. 
   
   
     29. A method as claimed in  claim 23  wherein the created holographic lens device is made to produce two bands of frequencies, for concentrating different bandwidths on different locations. 
   
   
     30. A method as claimed in  claim 29 , wherein one target is set to occupy PV transducers and the second target occupies heat sensitive elements. 
   
   
     31. A method as claimed in  claim 23 , further comprising providing a beam tilting element comprising at least one of said at least one of a plurality of layers of the electro-holographic lens devices, and tilting the focused light beam onto the target location.